Process for producing low density polyethylene compositions and polymers produced therefrom

Abstract

The present invention relates to an ethylene homo or copolymer characterized as having long chain branching, and having a molecular weight distribution, Mw/Mn, and a GPC-LALLS CDF, which satisfies the following relationship: y≧0.0663x−0.015, wherein y=GPC-LALLS CDF and x=Mw/Mn measured by conventional GPC, a line drawn from where the LS chromatogram intersects with molecular weight 350,000 and molecular weight 1,150,000 has a positive slope, preferably with a melt index between 0.15 and 2000 g/10 minutes and having long chain branching. In addition, the invention relates to a free radical initiation polymerization process for the preparation of ethylene polymers or copolymers, comprising reacting ethylene and optionally one or more comonomers at a high pressure, conveniently between 13,000 psig and 100,000 psig, and at reactor temperatures of 115° C. to 400° C., preferably 125-400° C., more preferably 140-350° C., especially 165-320° C., in a reactor system comprising at least one tubular, and at least one autoclave reactor, wherein the monomer(s) feed into the reactors is divided into multiple monomer feed streams, and wherein at least one feed stream into the tubular reactor consists essentially of unreacted monomer.

1. An ethylene homo or copolymer prepared in a high pressure radical initiated process using a chain transfer agent selected from the group consisting of saturated and unsaturated hydrocarbons, wherein the homo or copolymer is characterized as having long chain branching and having a molecular weight distribution, Mw/Mn, and a GPC-LALLS CDF, which satisfies the following relationship: y≧0.0663x−0.015, wherein y=GPC-LALLS CDF and x=Mw/Mn measured by conventional GPC; wherein a line drawn from where the LS chromatogram intersects with molecular weight 350,000 and molecular weight 1,150,000 has a positive slope; and wherein a film comprising the ethylene homo or copolymer has a microgel content of less than or equal to 3000 count, where microgels are defined as being in the range of 200-400 micron diameter gels per 50,000 square inches of film area. 
     
     
       2. The ethylene homo or copolymer according to  claim 1 , wherein the ethylene homo or copolymer has a melt index of from 0.15 to 2000 g/10 minutes, wherein the melt index is determined in accordance with ASTM D1238 condition (E) (190° C., 2.16 kg). 
     
     
       3. The ethylene homo or copolymer according to  claim 1  having a GPC Mw and a zero shear viscosity (η 0 ) (Pa*s) relationship of log(η 0  (Pa*s))≦3.6607*log(GPC Mw)−14.678. 
     
     
       4. The ethylene homo or copolymer according to  claim 1  having a melt strength of greater than or equal to about 75*(melt index) −0.6 , wherein the melt index is determined in accordance with ASTM D1238 condition (E) (190° C., 2.16 kg). 
     
     
       5. The ethylene homo or copolymer according to  claim 1  having a melt strength of greater than or equal to about 9.5*(melt index) −0.6 , wherein the melt index is determined in accordance with ASTM D1238 condition (E) (190° C., 2.16 kg). 
     
     
       6. The ethylene homo or copolymer according to  claim 1  having a melt strength of greater than or equal to about 11.5*(melt index) −0.6 , wherein the melt index is determined in accordance with ASTM D1238 condition (E) (190° C., 2.16 kg). 
     
     
       7. The ethylene homo or copolymer according to  claim 1  having a molecular weight distribution of between 2 and 7. 
     
     
       8. The ethylene homo or copolymer according to  claim 5  having a molecular weight distribution of between 4 and 7. 
     
     
       9. The ethylene homo or copolymer of  claim 1  in which the molecular weight distribution, Mw/Mn, and GPC-LALLS CDF satisfies the following relationship: y≧0.0663x−0.005. 
     
     
       10. The ethylene homo or copolymer of  claim 1  in which the molecular weight distribution, Mw/Mn, and GPC-LALLS CDF satisfies the following relationship: y≧0.0663x−0.025. 
     
     
       11. The ethylene homo or copolymer according to  claims 1 ,  9 , or  10 , wherein the polymer has a melt index of from 0.15 to 20 g/10 minutes, wherein the melt index is determined in accordance with ASTM D1238 condition (E) (190° C., 2.16 kg). 
     
     
       12. The ethylene homo or copolymer according to  claims 1 ,  9 , or  10 , wherein the polymer has a melt index of from 0.2 to 8 g/10 minutes, wherein the melt index is determined in accordance with ASTM D1238 condition (E) (190° C., 2.16 kg). 
     
     
       13. The ethylene homo or copolymer according to  claims 1 ,  9 , or  10 , wherein the polymer has a density of from 0.91 g/cm 3  to 0.935 g/cm 3 .